Performs basic math calculations (+ - * /) and compares data items to see which is larger
System clock
Electronic circuit that generates pulses (clock ticks) to synchronize computer's activities
Processor slots
Holds microprocessors in place
Heat sink/Cooling fan
Covers microprocessor and dissipates heat from the chip
Cooling can be performed by a fan or cooled liquid circulation
Power supply
Transforms alternating current (AC) to direct current (DC)
Lowers voltage to that required by motherboard
Speaker
Drive bays
Internal drives for data storage (operating system and application programs) are permanently installed in tower case (hard disk)
External drives are accessible and media (floppy disk, CD, DVD, zip disk) can be removed from drive bay
Basics for operation and performance
Benchmark -- a standard by which performance is judged
Compatibility -- the ability of using program instructions recognized by the CPU (Mac v. PC)
Downward compatibility allows a program to run on chips made earlier (check specs)
Performance
Data bus width -- the more paths data can run, the faster data can travel
Word size -- number of bits can more data faster (32-bit data bus can transfer twice as much data as a 16-bit)
CISC or RISC -- you decide...
Complex Instruction Set Computer (CISC) carries out many instructions at high speed
Microprocessor (see above)
Scalar or superscalar -- superscalar allows more than one instruction to be executed per clock cycle
Pipelining -- feeds a new instruction in every part of the machine cycle (Row, Row, Row Your Boat...)
Parallel processing -- many processors running at the same time
Memory (see below)
Memory
ROM
Read-Only Memory -- instructions to start the computer stored on ROM chips
ROM is non-volatile memory -- instructions do not go away when computer power is turned off
ROM stores computer BIOS (basic input/basic output) instructions to boot and test computer
ROM stores computer OS (operating system)
RAM
Random-Access Memory is volatile memory -- instructions go away when computer power is turned off
Application programs are stored temporarily in memory and data is temporarily stored in memory or moved to storage
Types of RAM (slowest to fastest) include DRAM (dynamic RAM), SDRAM synchronous DRAM, Rambus DRAM, DDR (double-data rate) SDRAM
Memory chips packaged as modules (slowest to fastest) SIMMs (single inline modules), DIMMs (dual inline modules)
Virtual memory
Computer can use the hard disk as an extension of RAM when running an OS (Windows, Linux, OS X)
CMOS
Complementary metal-oxide semiconductor - CMOS is volatile memory and requires a small amount of battery power to maintain information
Keeps track of amount of memory installed plus the current date and time
Cache
Cache is volatile memory that stores frequently-used instructions and data to speed up processing performance
Primary cache is L1 and is installed on the microprocessor chip
Secondary cache is L2 and is installed on its own circuit board
Input-output (I/0) buses
Provides the connection between input and output devices and the microprocessor
Contains expansion slots which hold expansion/adapter cards for input and output devices
Newer PCs and Macs use a Personal Computer Interface (PCI) bus which supports Plug and Play (PnP) which automatically detects and configures new devices to communicate with the computer
The System Unit
Motherboard- Central Processing Unit (CPU or microprocessor)
- Interprets instructions
- Carries out instructions by processing data and controlling computer's components
- Consists of two parts:
- Control Unit
- Coordinates computer system with four basic operations in the machine cycle:
- Fetch -- get next program instruction from computer's memory
- Decode -- figure out what the program is telling the computer to do
- Execute -- perform action based on program instruction
- Write -- send results to storage or to memory
- Intel "machine cycle" demo
- Arithmetic-Logic Unit (ALU)
- Performs basic math calculations (+ - * /) and compares data items to see which is larger
- System clock
- Electronic circuit that generates pulses (clock ticks) to synchronize computer's activities
- Processor slots
- Holds microprocessors in place
- Heat sink/Cooling fan
- Covers microprocessor and dissipates heat from the chip
- Cooling can be performed by a fan or cooled liquid circulation
Power supply- Transforms alternating current (AC) to direct current (DC)
- Lowers voltage to that required by motherboard
SpeakerDrive bays
Basics for operation and performance
Performance
Memory
Input-output (I/0) buses
Hardware Performance
Math Time
byte -- measures data size
Hertz -- measures cycles per second
Connectors (ports)